Six-sided exhaust stack



FIG. 1 is a perspective view thereof,

FIG. 2 is a front side view thereof,

FIG. 3 is a back side view thereof,

FIG. 4 is a top side view thereof,

FIG. 5 is a bottom side view thereof,

FIG. 6 is a left side view thereof; and,

FIG. 7 is a right side view thereof. 

CLAIM The ornamental design for a six-sided exhaust stack, as shown. 